如何设置HTML<select>元素的默认值？

Question

如何设置HTML<select>元素的默认值？

我以为增加一个"value"属性设置为<select>元素将导致<option>包含我提供的"value"默认情况下选择：

<select name="hall" id="hall" value="3">

  <option>1</option>

  <option>2</option>

  <option>3</option>

  <option>4</option>

  <option>5</option>

</select>

然而，这并不像我所预期的那样有效。我该怎么设置<option>元素是否默认选中？

Answer 1

集selected="selected"对于您希望成为默认选项的选项。<option selected="selected">3</option>

Answer 2

如果您希望将默认文本作为占位符/提示，但不认为是有效值(类似于“在此完成”，请“选择您的国家”ECC)。你可以这样做：<select>&nbsp;<option&nbsp;value=""&nbsp;selected&nbsp;disabled&nbsp;hidden>Choose&nbsp;here</option>&nbsp;<option&nbsp;value="1">One</option>&nbsp;<option&nbsp;value="2">Two</option>&nbsp; <option&nbsp;value="3">Three</option>&nbsp;<option&nbsp;value="4">Four</option>&nbsp;<option&nbsp;value="5">Five</option>&nbsp;</select>

Answer 3

完整的例子：<select name="hall" id="hall">&nbsp;&nbsp; <option>&nbsp;&nbsp; &nbsp; 1&nbsp;&nbsp; </option>&nbsp;&nbsp; <option>&nbsp;&nbsp; &nbsp; 2&nbsp;&nbsp; </option>&nbsp;&nbsp; <option selected>&nbsp;&nbsp; &nbsp; 3&nbsp;&nbsp; </option>&nbsp;&nbsp; <option>&nbsp;&nbsp; &nbsp; 4&nbsp;&nbsp; </option>&nbsp;&nbsp; <option>&nbsp;&nbsp; &nbsp; 5&nbsp;&nbsp; </option>&nbsp;</select>&nbsp;